Laminate surfaces are known for their economical cost and durable use. Common uses for laminate products include store fixtures, custom cabinets, desks or table tops, and kitchen countertops. Often, the laminated surfaces include a laminated radius edge.
Numerous methods exist for forming a laminate about a radius edge. In general, laminate is first applied to the surface of a core having a radius edge. The pre-applied laminate is secured to the core surface by any one of a number of methods as known in the art, such as by use of a contact adhesive. An adhesive layer on an under surface of the laminate secures the laminate to a similar layer on the surface of the core.
A portion of the laminate is left extending from a planar surface of the core to be secured to the radius edge. To secure the laminate to the radius edge, the laminated core is stabilized on a machine table. The laminate extending from the core may now be formed about the radius edge.
Present laminate-forming methods include the use of a longitudinally extending heat bar having a large pneumatic cylinder located at each end. In operation, the pneumatic cylinders move in a vertical direction to engage the heat bar with the laminate, heating the laminate to a temperature necessary for rendering the laminate sufficiently pliable to be bent around the radius edge. The heat bar is then removed. By pressing the laminate around the radius edge, the laminate is conformed to the edge to enable securement of the laminate to the radius edge.
The above methods of applying laminate to a radius edge fail to provide a uniform amount of heat longitudinally along the laminate to facilitate conforming the laminate to the radius edge. The heat bars, which often exceed ten feet in length, are supported by the pneumatic cylinders at the ends, and they can, as a result, bow in the middle.
In operation, when the heat bar presses the laminate against the radiused edge, heat is efficiently transferred to the laminate by conduction along the heat bar, which is located above the pneumatic cylinders. Since the heat bar tends to bow in the middle, air gaps can be created between the middle of the heat bar and the laminate, causing an inefficient transfer of radiant heat to the laminate surface. The non-uniform transfer of heat to the laminate surface along the radius edge can cause the laminate to be spaced from the core radiused edge at the center of the core due to the residual stress in the laminate.
In a similar method, relatively large pneumatic cylinders are located longitudinally beneath the heat bar. The heat bar contacts the laminate and is subsequently rotated about the radius edge to conform the laminate to the radiused edge. Holding adhesives such as Polyvinyl Acetate (PVA) can be used to secure the laminate to the core. The heat bar presses the laminate against the core until the PVA adhesive cures. Due to the size of the heat bar and pneumatic cylinders, this method of laminating particularly lends itself to the use of contact adhesives, such as a neoprene rubber adhesive, which require a method of cooling to set the adhesive for securing the laminate to the core.